Yes, sir, we’ll live with this until someone will put a stake through it’s heart:
Genes for red hair coloration may be older than Homo sapiens sapiens have been out of Africa.
Comments?
Jois
Yes, sir, we’ll live with this until someone will put a stake through it’s heart:
Genes for red hair coloration may be older than Homo sapiens sapiens have been out of Africa.
Comments?
Jois
Well, it would certainly explain an ex-girlfriend or two.
Seriously, though, I saw this story, I think on the UPI or the DPA or some such place. But does it appear in a peer-reviewed journal somewhere?
If you let yourself get worked up over every wild conjecture that makes the popular press, you’ll be old before your time.
Damn your hide, Jois!!
Now I have to print the linked article out, take it home to you-know-who, watch her fulminate for a while, have her write out a longhand response, and bring it in and type it out. Sheesh!!!
Can’t you do something provocative, like the incidence of bisexuality among monotheistic Homo rudolfensis or something?
BTW, thanks a million for all the material you’ve forwarded!
Manhatten, it was better when I could just take two aspirin and recall in the morning but Tylenol just isn’t the same.
Polycarp, these sites were recommended to me:
http://www.woodrow.org/teachers/bi/1997/makeface/bookrdhr.html
http://www.cpa.ed.ac.uk/news/research/28/3.html
Hair, eye and skin color are all inherited in mysterious ways, pretty darned scarey stuff.
Jois
Here’s another one -
http://www.keratin.com/ar/ar024.shtml
Shoot, maybe those Neanderthals all died off with skin cancer during the… forget I said that!
Jois
This link that Jois posted-- http://www.cpa.ed.ac.uk/news/research/28/3.html --says:
If it’s such a polymorphic trait, how come the Oxford researchers quoted in the Scotland on Sunday link can say so definitely, “We’ve pinned down THE gene for red hair in Neanderthals, and we’re sure this proves that Neanderthals and humans must have interbred”?
If they understand the genes for red hair “very little”, how come the Oxford researchers can say, “We’ve pinned down THE gene for red hair in Neanderthals, and we’re sure this proves that Neanderthals and humans must have interbred”?
If the genes for red hair are so polymorphic, how come the Oxford researchers quoted in the Scotland on Sunday link can say so definitely, “We’ve pinned down THE gene for red hair in Neanderthals, and we’re sure this proves that Neanderthals and humans must have interbred”?
What Manhattan said. Don’t get so worked up over oversimplified Sunday paper sound bites, Jois.
What lives you must lead if you think that’s worked up!
Jois
The Scots article is crap. Utter crap. (Of course I know you know that but this idiocy just makes me squirm)
DDG has captured a number of problems but let me note that its hard to tell where Harding is deriving her suppositions from. Hopefully the writer has butchered her thinking here.
First, maintaining a trait (I assume that is what is really meant) could not originate “in sweltering Africa” does not inspire confidence in the researcher. Unless she has actively excluded this, its rather unsupportable proposition to assert. And as we know, given the tide of evidence against Neandertal admixture (let alone the logical leap to connecting historical populations), her supposition strikes one as bizarre.
I should add that I did a quick literature search and was not able to turn up anything substantive. I hope that this is a case of reporter taking some words over beer and utterly misunderstanding them.
Collounsbury and Duck Duck Goose are absolutely right about the merits of the article, but I feel that I have to nitpick one thing: The use of the word “polymorphism.”
Polymorphism (meaning many forms, obviously) just means that a certain stretch of DNA comes in many forms across humans. There are several kinds of polymorphisms which we use for two general purposes: mapping and disease pathology.
One can do population genetics with RFLPs and STRs and SNPs to tack down a certain trait to a certain locus (or set of loci). Whether that specific locus is polymorphic is relatively secondary. For instance, the locus for Marfan syndrome is firmly pinned down to 15q21.1 (fibrillin locus). Most of the mutations are de novo, however, and not inherited – it happens to be a mutation hotspot – and therefore there are hundreds of catalogued nucleotide changes which may cause it.
The Marfan syndrome locus is higly polymorphic. But, we know where it is.
Awright, Edwino, you’re gonna haveta explain RFLP’s, SNP’s, and STR’s, or I’m gonna feel forced to do a fatherjohn on your butt.
[sup]or even worse, a peace.[/sup]
Neanderthals now have groupies who do see articles like this as reasonable and as support for what they, for goodness sakes, thought was right all along. Or if perhaps Harding went overboard on this one, someone else will come along, pop those Neanderthals into our genetic line and who knows what else. More wishful thinking than science.
Thank you for your responses and good info. I’d like to see more paleo/anthro/evolution threads here and have been looking for good topics. This one might not have been the best but I learned something.
And BTW, I almost know what RFLP’s, SNP’s, and STR’s mean!
Restriction Fragment Length Polymorphism
Sequence Tandum Repeat
But I give up on SNP!
Jois
Jois, you’re right about RFLP’s, but
STR = Simple Tandem Repeat
SNP = Single Nucleotide Polymorphism
Short (or Simple) Tandem Repeat
Single Nucleotide Polymorphism.
I was going to explain them, but it became to cumbersome (and a distraction from the OP).
A few things:
The word polymorphism is often used incorrectly by geneticists. It is often taken to be a disease-causing thing, but in fact it has no weight as either a good or a bad thing.
That said, some ground work:
As I mentioned, everybody has one chromosome from the mother and one from the father. These are not direct copies of the maternal/paternal chromosomes due to meiotic recombination which happens during germ cell formation. For instance, your mother has a chromosome 1 from her mother and her father, but your maternal chromosome 1 is a mix between her paternal and maternal chromosomes.
Next, there are many parts of the genome which vary widely in the population (polymorphisms). We use these as molecular landmarks along a huge chromosome. An easy to understand one is the STR (short tandem repeat), which is a simple bit of “junk” DNA repeated:
G(CA)[sub]n[/sub]G for instance.
if n=5 then
GCACACACACAG
An RFLP (restriction fragment length polymorphism) is another variable site in the genome. Basically, we have enzymes called restriction endonucleases which cleave DNA at a short inverted repeat sequence:
EcoRI =
GvAATTC
CTTAA^G
Let’s say there is a population variation in the genome where 10% of the people have a CAATTC instead of a GAATTC. EcoRI doesn’t recognize the site, and a digestion produces different sized bands which can be detected by separation of DNA fragments by gel electrophoresis (actually Southern blotting, the next series in the lecture… ) An RFLP.
SNPs are more common, and perhaps more important. These are usually found in coding regions, and determine how certain proteins are different in certain people. Perhaps these and other coding region (and enhancer) polymorphisms are what makes each of us different.
We can use polymorphisms for mapping (and paternity testing and a whole host of other things). Let’s take paternity testing. The Y chromosome is passed unchanged from father to son. Each male has 1 Y chromsome. Male A and Male B are duking it out as to who fathered Boy C. They both get paternity tested, which in the edwino Lab of Hypothetical Molecular Genetics involves testing 3 STRs. I count the “n” on each of the STRs:
[sub] STR #1 STR #2 STR#3
Male A 5 7 8
Male B 7 10 4
Child C 5 7 8[/sub]
Male A is Child C’s daddy (or maybe Male A’s brother or father). You get the picture.
You can do equivalent things with mapping – let’s say by pedigree that you know a disease allele is coming from a grandmother. This disease is dominant. 1/2 of the children have it, and 1/4 of the grandchildren. You can use STRs, RFLPs, SNPs, and the like to figure out exactly which piece of which chromsome came from the grandmother, as follows. The grandmother’s polymorphisms are labeled as A, the grandfather’s as B. All others are ignored (the spouses of the children). vB code is not the easiest way to do this, so bear with me here.
[sub]Grandmother Grandfather
AAAAAAAAAAA BBBBBBBBBBB
AAAAAAAAAAA BBBBBBBBBBB
Children
AAAAAAAAAAA
BBBBBBBBBBB
Grandchildren (after recomibination between A's and B's)
AAAABBBBAAA has disease
AABBBBAAABB has disease
ABBBAAAAAAB has disease
BBBBAAAAABB no disease
BBAAAAAABBB no disease[/sub]
Disease gene located somewhere near first A.
Sorry this looks so ugly, but I needed to make the fonts monotype to make it barely understandable. Anybody know how to make it look better?
Hope this clarifies some molecular human genetics for any of you still paying attention.
I just realized that the numbers don’t jibe with the above grandmother-disease allele example. It could be understood that the grandmother is homozygous for a dominant trait, the children are heterozygotes, and 1/2 of the grandchildren are heterozygotes. This would make the disease frequency 100% among the children and 50% among the grandchildren.
Sorry.
Yes, some are still reading and thinking! Thanks you, Jois